1. Field of Art
This invention relates to the improvement of a feederhouse on an agricultural combine. More specifically, the invention allows for the acoustic detection and ejection of a stone from the feederhouse.
2. Description of Prior Art
Mechanical harvesting of grain has taken place for decades. However, efforts continue in the attempt to make harvesting operations more efficient and effective. A combine harvester generally includes a header, which cuts the crop. The header then moves the cut crop into a feeder house. The feeder house lifts the cut crop into the threshing and separation areas of the combine. The grain is separated from the stalk by a rotor or threshing system. The grain is then moved and stored in a grain tank. The chaff and trash are deposited from the rear of the combine. The grain stored in the grain tank is eventually discharged through a grain tank unload tube. An operator usually runs these various operations from a glass-enclosed cab. Typically, the cab is located above and behind the header and feederhouse. There are a variety of agricultural combine harvesters and their operations are well known in the art. For examples of such harvesters reference U.S. Pat. No. 4,846,198 which illustrates the conventional and twin rotor threshing and separating systems of a harvester as well as other major systems of the harvester. See also the New Holland Super Conventional Combines TX.TM. 66, TX.TM. 68, the New Holland TWIN ROTOR.RTM. combines TR.RTM. 89 and TR.RTM. 99 for examples of existing conventional and twin rotor harvesters. U.S. Pat. No. 4,332,262 also illustrates the primary systems of a conventional harvester. For further details regarding various agricultural harvester systems review U.S. Pat. Nos. 4,522,553, 4,800,711, 4,866,920, 4,907,402, 4,967,544 and 5,155,984. See also the New Holland corn head model 996 and the New Holland grain belt header model 994 for details regarding headers.
The previously mentioned a feederhouse typically consists of a conveying chain which pushes the cut crop from the header to the front of the threshing system. The conveying chain has several crosspieces to assist in moving the crop and to ensure proper spacing. The conveying chain is powered and also positioned by a front drum and a rear drum. The front drum is positioned approximately behind the header and the rear drum is positioned approximately in front of the threshing system. As seen in FIG. 1, the drums rotate in a counter-clockwise fashion. The cut crop flow or crop mat is pushed by conveyor chain upwards along the floor of the feederhouse and towards the threshing system. Besides lifting or elevating the cut crop to the threshing and separating systems, the feederhouse provides several other functions. First, the feederhouse helps to properly position the header relative to the ground. Second, the feederhouse can be the location of a stone detection and removal means. Frequently, during farming operations, the header will inadvertently receive a stone. If the stone enters the threshing system in the combine, expensive damage will result to the threshing components. It is a critical function of a stone detection and removal system to prevent a stone from damaging the threshing system. A typical stone detection and removal system is a cylindrical stone beater or stone roll positioned near the mid-point of the feederhouse. The stone roll rotates allowing the crop mat to continue towards the rear drum and threshing system. A stone that is too large is forced from the feederhouse through a stone trap door beneath the stone roll.
Unfortunately there are several deficiencies to the current feederhouse design. The stone beater design limits the thickness of the crop flow. By limiting the amount of crop flow, it takes longer to perform farming operations. Previously, acoustic instruments have been used to detect stones entering farm equipment. Typically, the stone contacts a sounding plate. The acoustic instrument monitors the sounding plate. A stone contacting the sounding plate causes the sounding plate to emit a sound above a pre-determined setting. The acoustic instrument observes this sound and halts the farming operation. It has been difficult to apply this technique of stone detection to a combine harvester. Typically if a single acoustic instrument and sounding plate is used, a stone can only be detected on the side of the crop flow closest to the detector. Stones on the opposite side or center of the crop flow are undetected. There are also additional problems with the feederhouse design. Conventional stone traps remain unlatched during farming operations. A malfunction with the spring mechanism used to keep the door closed can result in crop being inadvertently forced through the stone trap door.
The prior art illustrates these and other short-comings. U.S. Pat. No. 3,675,660 discloses a combine stone trap door premised on the rock detector circuit opening the stone trap door. It is possible that that the stone may be embedded in the crop flow and not deflected to be discharged. U.S. Pat. No. 4,275,546 discloses a stone discriminator using a single sounding plate to detect stones. This approach is unable to detect stones in the upper portion of the crop flow. It has not been able to successfully detect and eject stone sufficiently to be commercially viable. U.S. Pat. No. 4,288,969 discloses an improved stone trap seal. However, because of the angle of the conveying chain, a greater amount of crop is deflected and wasted. U.S. Pat. No. 4,294,062 discloses single sensing bar positioned at the bottom of the feederhouse and unable to sufficiently detect stones. U.S. Pat. Nos. 4,305,244, 4,322,933 and 4,343,137 illustrates a feeder house design for a combine. The lower sensing bar is used to trigger the stone trap door. However, the single sensing bar does not sufficiently detect the stones and the angle of the conveying chain results in more crop being deflected than necessary. U.S. Pat. No. 4,355,565 uses a mechanical stone beater bar to force a stone out of the crop flow. However, if the stone is too small or flat, the stone will not be detected or ejected. Also, the stone beater is only effective at lower speeds. U.S. Pat. No. 4,353,199 illustrates a single sensing bar used in a forage harvester. U.S. Pat. No. 4,768,525 illustrates a stone ejection door mechanism for harvesting equipment having a front and rear stone trap doors. U.S. Pat. No. 4,720,962 illustrates a single sensor that can be positioned in a variety of locations on a forage harvester. U.S. Pat. No. 5,702,300 illustrates a combine rock door over center closure apparatus shows a lever used to control a stone trap door.
An invention that could resolve these issues would represent an improvement to the art.